package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.ScrollResult;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;
import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 * 服务实现类（修复后）
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private IUserService userService;

    @Resource
    private IFollowService followService;

    /**
     * 修复：实现博客保存逻辑，补充默认值
     */
    @Override
    public Result saveBlog(Blog blog) {
       UserDTO user = UserHolder.getUser();
       blog.setUserId(user.getId());
       boolean isSuccess = save(blog);
       if (!isSuccess) {
           return  Result.fail("新增笔记失败");
       }
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
        for (Follow follow : follows) {
            Long userId = follow.getUserId();
            String key = FEED_KEY + userId;
            stringRedisTemplate.opsForZSet().add(key,blog.getId().toString(),System.currentTimeMillis());
        }
        return Result.ok();
    }

    /**
     * 查询博客详情（修复空指针风险）
     */
    @Override
    public Result queryBlogById(Long id) {
        // 1. 查询博客
        Blog blog = getById(id);
        if (blog == null) {
            return Result.fail("笔记不存在");
        }

        // 2. 补充用户信息（已修复空指针）
        queryBlogUser(blog);

        return Result.ok(blog);
    }

    /**
     * 查询热点博客（修复分页信息丢失）
     */
    @Override
    public Result queryHotBlog(Integer current) {
        // 1. 分页查询热点博客（按点赞数降序）
        Page<Blog> page = query()
                .orderByDesc("liked") // 按点赞数倒序
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));

        // 2. 为当前页博客补充用户信息
        List<Blog> records = page.getRecords();
        records.forEach(this::queryBlogUser);

        // 3. 返回完整分页对象（包含总条数、当前页等信息）
        return Result.ok(page);
    }

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Override
    public Result queryBlogLikes(Long id) {
        String key = BLOG_LIKED_KEY + id;
        // 1.查询top5的点赞用户 zrange key 0 4
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if (top5 == null || top5.isEmpty()) {
            return Result.ok(Collections.emptyList());
        }
        // 2.解析出其中的用户id
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idStr = StrUtil.join(",", ids);
        // 3.根据用户id查询用户 WHERE id IN ( 5 , 1 ) ORDER BY FIELD(id, 5, 1)
        List<UserDTO> userDTOS = userService.query()
                .in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        // 4.返回
        return Result.ok(userDTOS);
    }

    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        // 1.获取当前用户
        Long userId = UserHolder.getUser().getId();
        // 2.查询收件箱 ZREVRANGEBYSCORE key Max Min LIMIT offset count
        String key = FEED_KEY + userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        // 3.非空判断
        if (typedTuples == null || typedTuples.isEmpty()) {
            return Result.ok();
        }
        // 4.解析数据：blogId、minTime（时间戳）、offset
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0; // 2
        int os = 1; // 2
        for (ZSetOperations.TypedTuple<String> tuple : typedTuples) { // 5 4 4 2 2
            // 4.1.获取id
            ids.add(Long.valueOf(tuple.getValue()));
            // 4.2.获取分数(时间戳）
            long time = tuple.getScore().longValue();
            if(time == minTime){
                os++;
            }else{
                minTime = time;
                os = 1;
            }
        }
        os = minTime == max ? os : os + offset;
        // 5.根据id查询blog
        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();

        for (Blog blog : blogs) {
            // 5.1.查询blog有关的用户
            queryBlogUser(blog);
            // 5.2.查询blog是否被点赞
            isBlogLiked(blog);
        }

        // 6.封装并返回
        ScrollResult r = new ScrollResult();
        r.setList(blogs);
        r.setOffset(os);
        r.setMinTime(minTime);

        return Result.ok(r);
    }

    private void isBlogLiked(Blog blog) {

    }

    /**
     * 为博客补充用户信息（修复空指针风险）
     */
    private void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        if (userId == null) {
            return; // 无用户ID，无需处理
        }

        // 查询用户（处理用户不存在的情况）
        User user = userService.getById(userId);
        if (user != null) {
            blog.setName(user.getNickName()); // 补充用户名
            blog.setIcon(user.getIcon());     // 补充用户头像
        } else {
            // 用户不存在时设置默认值，避免空指针
            blog.setName("未知用户");
            blog.setIcon(""); // 空头像路径
        }
    }
}